The present invention pertains to the latch and locking art. It finds particular application in conjunction with latching a door to medical sterilizing equipment with sufficient force that a fluid tight seal is created. It is to be appreciated, however, that the present latching mechanism will also find application in locking or sealing doors to retain other fluids, in deep sea applications, in space applications, in sealing against hazardous vapor and fluid contamination, and in other applications in which a very high sealing force is advantageous. Moreover, the present invention also has security application in which doors, windows, and other movable elements are to be locked and resist tampering.
Prior U.S. patent application Ser. No. 07/681,118 describes a sterilizing apparatus in which an access door is vacuum sealed in a closed position during operation. That is, the door opens to allow access to a sterilization chamber, a sterilant mixing chamber, and various liquid sterilant flow paths. After the equipment to be sterilized is loaded into the sterilizing chamber and a dose of sterilant concentrate is loaded into the mixing chamber, the door is closed. The door is held closed by drawing a vacuum between a pair of circumferential gaskets around the periphery of the door.
Although the vacuum seal created a secure fluid tight seal under normal operating conditions, it is considered undesirable to have fluid leakage even under abnormal operating conditions. For example, dropping a heavy object on the door or banging the door with a cabinet door or elbow could jar the sterilizer door sufficiently to allow a momentary fluid leakage. Moreover, with age, the rubber gaskets would tend to seal less well, reducing the vacuum seal and, hence, the reliability.
Various mechanical hooking mechanisms are known in the art. For example, rigid, pivoted hooks have been used which slidingly engage and cam a latch pin. However, such rigid, pivoted hooks tend to require a relatively high latching pressure. Further, the camming action causes wear on the latch pin, allowing the latching to become sloppy or loose with repeated use. Multi-piece latches with an internal gear arrangement have been successful in obtaining a relatively high holding force with a relatively small closing force. However, the mechanical linkages tended to be complex, difficult to adjust, and subject to damage or deformation.
In accordance with the present invention, a new and improved latching mechanism is provided which achieves a very high holding force with a very small closing force.